Conventionally, beverage dispensing systems require electrical or gasoline power. Therefore, these systems tend to be bulky and usually are unsuitable for portable applications. Typically, such conventional beverage dispensing systems comprise a high pressure carbonator tank plumbed to a carbon dioxide (CO.sub.2) cylinder through a pressure regulator in which the pressure to be supplied to the carbonator tank is reduced to approximately 90 pounds per square inch (psi). A motorized pump plumbed to a fixed water tap system is used to pressurize the water supplied to the tank to approximately 200 psi. The high pressure water flows into the carbonator tank, overcoming the rising pressure of the CO.sub.2 gas contained therein. As the carbonator tank fills with this high pressure water, a pocket of CO.sub.2 gas that exists above the water is compressed, forcing the CO.sub.2 gas to be absorbed into the water, thereby creating carbonated water.
In that the conventional beverage dispensing systems described above require a constant source of power to operate the pump motor, use of such systems is generally limited to fixed installations. Although portable beverage dispensing systems that do not require electrical or gasoline powered pumps have been developed, these systems have several disadvantages. One such system is disclosed in U.S. Pat. No. 5,411,179 (Oyler et al.) and U.S. Pat. No. 5,553,749 (Oyler et al.). Similar to the systems described in the present disclosure, the systems described in these patents use high pressure CO.sub.2 gas supplied by a CO.sub.2 tank to pressurize the water that is supplied to a carbonator tank. Unlike the systems described in the present disclosure, however, the systems described in these patent references use low pressure carbonator tanks which typically operate at pressures below 100 psi.
Despite providing for some degree of water carbonation (typically approximately 2.5%), known systems typically do not produce beverages having a commercially acceptable level of carbonation (generally between 3.0% to 4.0%). Experimentation has shown that the pressurized water often must be cooled to a low temperature prior to entering the carbonator tank of these systems to achieve fill absorption of CO.sub.2 gas into the water. Moreover, the CO.sub.2 gas that is absorbed into the carbonated water can quickly be diffused from the water when it is heated to a warmer temperature. Accordingly, when the carbonated water is post-mixed with relatively warm liquids, such as concentrated syrups, juices, and the like, the relatively small amount of carbonation of the water quickly can be lost.
It therefore can be appreciated that it would be desirable to have a self-contained beverage dispensing system that is portable and which produces beverages having a commercially acceptable level of stable carbonation.